ALL the "regular" commentators do a JAM UP job.
And that's that. Even Jim Wych (who I used to hate, because of his off kilter delivery) hits the mark more often than not, and I don't mind him at all anymore.
My ranking in terms of the EFFECTIVENESS of their commentary:
Danny Diliberto (You can tell his eyes might be going a little, because sometimes he sees angles just a little "off", but when he sees the angles correctly, he calls the shot dead on 98% of the time.)
Grady (for his personality. He is on par with Billy as far as predicting correctly)
Billy (was never accused of being humble.

He also incorrectly guesses the shots in One Pocket more often commentating top players, because he has "turned off" his aggressiveness in One Pocket to a certain extent. Danny is MUCH more often on track when commentating One Pocket, IMHO. Billy is enjoyable to listen to for his response to Efren's magic.

)
Jim Wych and Jerry Forsythe are on par for effectiveness. Forsythe is ahead on enjoyability.
Jay Helfert. I LIKE Jay's commentary BTW, more than Forsythe or Jim Wych.. But sometimes he's a little off on predicting what players are gonna do in One Pocket. Nothing against Jay whatsoever on this. He has a great commentary voice, and is 1000% better technically and aesthetically than Martin Courteois (sp? Coor-TWAH)
Martin Courteois (If Accu-Stats ever lets this man commentate again, I'll go there personally and murder everyone in the company. That's how bad I HATE his commentary. Not even putting Danny D. in the booth with him can make a match with him commentating watchable.)
Russ